ACT Policing officers and State Emergency Service volunteers searched land next to Hindmarsh Drive in Red Hill on Thursday morning.

Police said the "routine search" was linked to the homicide of Miodrag Gajic, 71, who was found dead with significant head injuries in his Mansfield Place unit on New Year's Day.

At least six officers, including police and SES personnel, searched methodically up the east-bound lane of Hindmarsh Drive on Wednesday morning, picking through scrub and bush-land.

While the main search took place in the native bush alongside Red Hill, others SES members were seen further down the road on the reserve near Garran.

The investigation into the killing has entered its third week, and the Red Hill search comes just one day after detectives went public with calls for two potentially crucial witnesses to come forward.

The two women possibly saw Mr Gajic's killer coming in or out of the small apartment complex in Phillip on New Year's Day.

Police have refused to comment on whether they suspect a weapon was used in the killing, and haven't revealed the exact nature of Mr Gajic's injuries.

The Canberra Times revealed on Saturday that a man linked with the killing had already been taken off the streets in relation to other charges.

It is understood that a second man, well known in criminal circles, has also been taken in for questioning.

Mr Gajic was thought to have been found several hours after he was killed, about mid-morning on New Year's Day.

Neighbours, who described Mr Gajic as "reclusive" but also as a "good bloke", reported hearing screams as the discovery of the elderly man's body was made.

Mr Gajic was known to police prior to his death, and is suspected of dealing cannabis out of the unit.

The elderly man had family, and had previously worked as a butcher, before an injury forced him out of the trade.

Thursday's search took place as temperatures on the side of the road pushed 35 degrees.

Residents with properties backing onto the reserve said they hadn't been informed of the search and officers on the scene wouldn't comment on what they were looking for.

Anyone with information should contact Crime Stoppers on 1800 333 000 or via the website.

- with Ben Westcott